We test visual performance after LASIK (laser in situ keratomileusis) for a Q-optimized ablation algorithm and one based on the Munnerlyn formula. The visual functions tested include aberrometry, monocular and binocular contrast sensitivity function (CSF), and a discrimination test under low-illumination conditions. This test is useful to quantify night-vision disturbances. A total of 102 patients took part in the experiments, and visual data were taken before (with best correction) and after LASIK. Results show a deterioration in aberrometry, CSF, binocular summation, and discrimination index for the two algorithms tested, although this deterioration is significantly lower for the Q-optimized algorithm.